Closes Top-10 fix#2 of the 2026-05-03 issuer-coverage audit (see
cowork/issuer-coverage-audit-2026-05-03/RESULTS.md). Pre-fix,
vault.Config.Token and digicert.Config.APIKey were plain string
fields. Practical impact:
1. GET /api/v1/issuers responses marshalled the credential into
the JSON body. An acquirer's procurement engineer running
'curl /api/v1/issuers | jq' saw the token / API key in plain
text on screen.
2. DEBUG-level HTTP request logging printed the credential
header verbatim.
3. A heap dump of the running server contained the credential
as readable bytes for the lifetime of the process.
Bundle I from the 2026-05-01 audit closed this for AWSACMPCA,
EJBCA, GlobalSign, Sectigo (Phase 1+2). Vault and DigiCert were
left out. This commit ports the same migration onto them.
Mechanics:
- Config.Token / Config.APIKey type changed from 'string' to
'*secret.Ref'. UnmarshalJSON of a JSON string populates the
Ref via NewRefFromString — operator config files are
unchanged.
- Every header-write call site routed through Ref.Use, with the
byte buffer zeroed after the callback returns. Vault: 3 sites
(IssueCertificate, RevokeCertificate, GetCACertPEM). DigiCert:
5 sites (ValidateConfig, IssueCertificate, RevokeCertificate,
pollOrderOnce, downloadCertificate).
- ValidateConfig nil-checks switch from 'cfg.Token == ""' to
'cfg.Token.IsEmpty()' (mirrors Sectigo's existing pattern).
- Tests migrated: every Config{Token:"..."} →
Config{Token: secret.NewRefFromString("...")}. The
'json.Marshal(config) → ValidateConfig(rawConfig)' round-trip
pattern in DigiCert's ValidateConfig_Success test is now
broken by the redact-on-marshal contract — switched that one
to construct the rawConfig as a JSON literal (mirrors
Sectigo's existing test pattern).
- Two new tests pin the redact-on-marshal contract:
- TestVault_Config_TokenMarshalsAsRedacted (vault_redact_test.go)
- TestDigiCert_Config_APIKeyMarshalsAsRedacted (digicert_redact_test.go)
Both assert the marshaled JSON contains '"[redacted]"' and
does NOT contain the plaintext bytes.
Operator-visible: GET /api/v1/issuers responses for type=vault
and type=digicert now show the credential as '[redacted]'.
Existing config files keep working — the Ref unmarshal accepts
strings.
CHANGELOG note: certctl/CHANGELOG.md is intentionally not
hand-edited; release notes are auto-generated from commit
messages between consecutive tags. This commit's message body is
the release-note artifact.
Verified locally:
- gofmt clean across the repo.
- go vet ./... clean across the repo.
- go test -race -count=1 -short
./internal/connector/issuer/vault/...
./internal/connector/issuer/digicert/...
./internal/secret/... green.
Audit reference: cowork/issuer-coverage-audit-2026-05-03/
RESULTS.md Top-10 fix#2.
shankar0123